Parents and other infant caregivers use many methods for mixing and heating baby formula. Typically, a caregiver measures an amount of powdered formula and an amount of water, places the measured water and formula into a bottle, and shakes the bottle to mix the formula.
The water, or the mixed formula, may be heated on a stove top or in a microwave oven. Also, specialized bottle warmers have been developed, which use steam for heating bottled formula. Such bottle warmers may include a bottom compartment for holding water and a top compartment for receiving a bottle to be heated. To heat the bottle, the caregiver fills the bottom compartment with water, places a bottle in the top compartment, and plugs in the bottle warmer. The machine boils the water, and steam rises into the top compartment to gradually heat the bottle and its contents.